The present invention relates to combined cycle electric power plants and more particularly to improved digital/analog hybrid control systems especially useful in the operation of gas turbines in combined cycle electric power plants.
In the manufacture of combined cycle and other electric power plants, it is desirable that they be structured to be characterized with high operating availability for power generation. Control system and other equipment operating reliability is one important factor in the plant availability rating. Control system reliability in turn depends both on the reliability of parts of the control system as well as the manner in which the system parts are organized to provide the desired turbine performance and protection.
Digital/analog control systems can be hybridized in varying ways to provide specific control performance while control system reliability and cost depend on the system organization. The previously noted patent application Ser. No. 319,114 discloses a digital/analog hybrid control system which is arranged to operate a gas turbine electric power plant. In another patent application Ser. No. 476,182 entitled "Local Maintenance Controller For Gas Turbine Power Plants Having A Primary Control System " filed by R. A. Yannone et al on June 4, 1974 and assigned to the present assignee, there is disclosed a backup control system usable with the hybrid control system of Ser. No. 319,114 to obtain extended system reliability. In the previously noted patent application Ser. No. 371,625, there is disclosed another control system and the manner in which it is organized to achieve high gas turbine operating reliability.
The present patent application is directed to an improved digital/analog hybrid control system especially adapted for operating gas turbines and other equipment in a combined cycle electric power plant.
The description of the prior art herein is made on good faith and no representation is made that any prior art considered is the best pertaining prior art nor that the interpretation placed on it is unrebuttable.